I have used mineral spirits and can tell you it will not work as well as real flush. There must be something in the flush chemical that breaks surface tension or acts as a detergent, because I have followed up with flush AFTER using mineral spirits and gotten lots of debris. Just my $.02 - go with the real thing.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280